Techniques and apparatuses for control channel monitoring using a wakeup signal

ABSTRACT

Techniques described herein use a wakeup signal to indicate to a user equipment (UE) whether an upcoming control channel signal resource includes information relevant to the UE. In this way, the UE can wake up to perform complex control channel signal processing only when the control channel includes signals relevant to the UE, thereby conserving battery power and resources of the UE. Such techniques are particularly suited to MTC UEs, NB-IoT UEs, and/or the like, which may communicate with a network only occasionally, and which may be located in remote locations where changing or recharging a battery is difficult.

CROSS-REFERENCE TO RELATED APPLICATIONS UNDER 35 U.S.C. § 119

This application claims priority to Indian Patent Application No.201741009311, filed Mar. 17, 2017, entitled “TECHNIQUES AND APPARATUSESFOR CONTROL CHANNEL MONITORING USING A WAKEUP SIGNAL,” which is herebyexpressly incorporated by reference herein.

BACKGROUND Field

Aspects of the present disclosure generally relate to wirelesscommunication, and more particularly to techniques and apparatuses forcontrol channel monitoring using a wakeup signal.

Background

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power, and/or the like). Examples of such multiple-accesstechnologies include code division multiple access (CDMA) systems, timedivision multiple access (TDMA) systems, frequency-division multipleaccess (FDMA) systems, orthogonal frequency-division multiple access(OFDMA) systems, single-carrier frequency-division multiple access(SC-FDMA) systems, time division synchronous code division multipleaccess (TD-SCDMA) systems, and Long Term Evolution (LTE).LTE/LTE-Advanced is a set of enhancements to the Universal MobileTelecommunications System (UMTS) mobile standard promulgated by theThird Generation Partnership Project (3GPP).

A wireless communication network may include a number of base stations(BSs) that can support communication for a number of user equipment(UEs). A UE may communicate with a BS via the downlink and uplink. Thedownlink (or forward link) refers to the communication link from the BSto the UE, and the uplink (or reverse link) refers to the communicationlink from the UE to the BS. As will be described in more detail herein,a BS may be referred to as a Node B, a gNB, an access point (AP), aradio head, a transmit receive point (TRP), a 5G BS, a 5G Node B, and/orthe like.

The above multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless communication devices to communicate on a municipal,national, regional, and even global level. 5G, which may also bereferred to as New radio (NR), is a set of enhancements to the LTEmobile standard promulgated by the Third Generation Partnership Project(3GPP). 5G is designed to better support mobile broadband Internetaccess by improving spectral efficiency, lowering costs, improvingservices, making use of new spectrum, and better integrating with otheropen standards using OFDM with a cyclic prefix (CP) (CP-OFDM) on thedownlink (DL), using CP-OFDM and/or SC-FDM (e.g., also known as discreteFourier transform spread ODFM (DFT-s-OFDM)) on the uplink (UL), as wellas supporting beamforming, multiple-input multiple-output (MIMO) antennatechnology, and carrier aggregation. However, as the demand for mobilebroadband access continues to increase, there exists a need for furtherimprovements in LTE and 5G technologies. Preferably, these improvementsshould be applicable to other multiple access technologies and thetelecommunication standards that employ these technologies.

When in an idle mode or a connected mode discontinuous reception (CDRX)mode, a UE may enter a low power state to conserve battery power, andmay periodically wake up to monitor a control channel for signalsrelating to the UE, such as pages. However, such control channelmonitoring may be resource intensive and may consume battery powerbecause the control channel uses complex signals that include a largeamount of information. For example, the UE may wake up, search forsignals on the control channel, decode the signals if the signals arefound, and determine whether the decoded signals are relevant to the UE.If the decoded control channel signals are not relevant to the UE or ifno control channel signal is found, then the battery power used tosearch for, receive, and decode the control channel signals is wasted.

SUMMARY

Techniques described herein use a wakeup signal to indicate to a UEwhether an upcoming control channel signal resource includes informationrelevant to the UE. In this way, the UE wakes up to perform complexcontrol channel signal processing only when the control channel includessignals relevant to the UE, thereby conserving battery power andresources of the UE. Such techniques are particularly suited tomachine-type communication (MTC) UEs, narrowband Internet of Things(NB-IoT) UEs, and/or the like, which may communicate with a network onlyoccasionally, and which may be located in remote locations wherechanging or recharging a battery is difficult.

In an aspect of the disclosure, a method, a user equipment, a basestation, an apparatus, and a computer program product are provided.

In some aspects, the method may include identifying, by a user equipment(UE), a wakeup signal resource associated with the UE based at least inpart on a control channel search space resource associated with the UE,wherein the wakeup signal resource maps to the control channel searchspace resource and precedes the control channel search space resource;monitoring, by the UE, the wakeup signal resource for an indication ofwhether to monitor the control channel search space resource; andselectively monitoring, by the UE, the control channel search spaceresource based at least in part on the indication of whether to monitorthe control channel search space resource.

In some aspects, the method may include identifying, by a base station,a wakeup signal resource associated with a UE based at least in part ona control channel search space resource associated with the UE, whereinthe wakeup signal resource maps to the control channel search spaceresource and precedes the control channel search space resource;determining, by the base station, whether a control channel searchspace, associated with the control channel search space resource, is toinclude control information associated with the UE; and selectivelytransmitting, by the base station, a wakeup signal in the wakeup signalresource based at least in part on determining whether the controlchannel search space is to include control information associated withthe UE.

In some aspects, the UE may include a memory and one or more processorscoupled to the memory. The one or more processors may be configured toidentify a wakeup signal resource associated with the UE based at leastin part on a control channel search space resource associated with theUE, wherein the wakeup signal resource maps to the control channelsearch space resource and precedes the control channel search spaceresource; monitor the wakeup signal resource for an indication ofwhether to monitor the control channel search space resource; andselectively monitor the control channel search space resource based atleast in part on the indication of whether to monitor the controlchannel search space resource.

In some aspects, the base station may include a memory and one or moreprocessors coupled to the memory. The one or more processors may beconfigured to identify a wakeup signal resource associated with a UEbased at least in part on a control channel search space resourceassociated with the UE, wherein the wakeup signal resource maps to thecontrol channel search space resource and precedes the control channelsearch space resource; determine whether a control channel search space,associated with the control channel search space resource, is to includecontrol information associated with the UE; and selectively transmit awakeup signal in the wakeup signal resource based at least in part ondetermining whether the control channel search space is to includecontrol information associated with the UE.

In some aspects, the apparatus may include means for identifying awakeup signal resource associated with the apparatus based at least inpart on a control channel search space resource associated with theapparatus, wherein the wakeup signal resource maps to the controlchannel search space resource and precedes the control channel searchspace resource; means for monitoring the wakeup signal resource for anindication of whether to monitor the control channel search spaceresource; and means for selectively monitoring the control channelsearch space resource based at least in part on the indication ofwhether to monitor the control channel search space resource.

In some aspects, the apparatus may include means for identifying awakeup signal resource associated with a UE based at least in part on acontrol channel search space resource associated with the UE, whereinthe wakeup signal resource maps to the control channel search spaceresource and precedes the control channel search space resource; meansfor determining whether a control channel search space, associated withthe control channel search space resource, is to include controlinformation associated with the UE; and means for selectivelytransmitting a wakeup signal in the wakeup signal resource based atleast in part on determining whether the control channel search space isto include control information associated with the UE.

In some aspects, the computer program product may include one or moreinstructions for wireless communication. The one or more instructions,when executed by one or more processors, may cause the one or moreprocessors to identify a wakeup signal resource associated with a UEbased at least in part on a control channel search space resourceassociated with the UE, wherein the wakeup signal resource maps to thecontrol channel search space resource and precedes the control channelsearch space resource; monitor the wakeup signal resource for anindication of whether to monitor the control channel search spaceresource; and selectively monitor the control channel search spaceresource based at least in part on the indication of whether to monitorthe control channel search space resource.

In some aspects, the computer program product may include one or moreinstructions for wireless communication. The one or more instructions,when executed by one or more processors, may cause the one or moreprocessors to identify a wakeup signal resource associated with a UEbased at least in part on a control channel search space resourceassociated with the UE, wherein the wakeup signal resource maps to thecontrol channel search space resource and precedes the control channelsearch space resource; determine whether a control channel search space,associated with the control channel search space resource, is to includecontrol information associated with the UE; and selectively transmit awakeup signal in the wakeup signal resource based at least in part ondetermining whether the control channel search space is to includecontrol information associated with the UE.

Aspects generally include a method, apparatus, system, computer programproduct, non-transitory computer-readable medium, user equipment, basestation, wireless communication device, and processing system assubstantially described herein with reference to and as illustrated bythe accompanying drawings and specification.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is diagram illustrating an example of a wireless communicationnetwork.

FIG. 2 is a diagram illustrating an example of a base station incommunication with a user equipment (UE) in a wireless communicationnetwork.

FIG. 3 is a diagram illustrating an example of a frame structure in awireless communication network.

FIG. 4 is a diagram illustrating two example subframe formats with thenormal cyclic prefix.

FIG. 5 is a diagram illustrating an example logical architecture of adistributed radio access network (RAN).

FIG. 6 is a diagram illustrating an example physical architecture of adistributed RAN.

FIG. 7 is a diagram illustrating an example of a downlink (DL)-centricwireless communication structure.

FIG. 8 is a diagram illustrating an example of an uplink (UL)-centricwireless communication structure.

FIG. 9 is a diagram illustrating an example of control channelmonitoring using a wakeup signal.

FIG. 10 is a diagram illustrating another example of control channelmonitoring using a wakeup signal.

FIG. 11 is a flow chart of a method of wireless communication.

FIG. 12 is a flow chart of another method of wireless communication.

FIG. 13 is a conceptual data flow diagram illustrating the data flowbetween different modules/means/components in an example apparatus.

FIG. 14 is a diagram illustrating an example of a hardwareimplementation for an apparatus employing a processing system.

FIG. 15 is a conceptual data flow diagram illustrating the data flowbetween different modules/means/components in another example apparatus.

FIG. 16 is a diagram illustrating another example of a hardwareimplementation for an apparatus employing a processing system.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purposes of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well-known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, modules, components,circuits, steps, processes, algorithms, and/or the like (collectivelyreferred to as “elements”). These elements may be implemented usingelectronic hardware, computer software, or any combination thereof.Whether such elements are implemented as hardware or software dependsupon the particular application and design constraints imposed on theoverall system.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented with a “processing system”that includes one or more processors. Examples of processors includemicroprocessors, microcontrollers, digital signal processors (DSPs),field programmable gate arrays (FPGAs), programmable logic devices(PLDs), state machines, gated logic, discrete hardware circuits, andother suitable hardware configured to perform the various functionalitydescribed throughout this disclosure. One or more processors in theprocessing system may execute software. Software shall be construedbroadly to mean instructions, instruction sets, code, code segments,program code, programs, subprograms, software modules, applications,software applications, software packages, routines, subroutines,objects, executables, threads of execution, procedures, functions,and/or the like, whether referred to as software, firmware, middleware,microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the functions describedmay be implemented in hardware, software, firmware, or any combinationthereof. If implemented in software, the functions may be stored on orencoded as one or more instructions or code on a computer-readablemedium. Computer-readable media includes computer storage media. Storagemedia may be any available media that can be accessed by a computer. Byway of example, and not limitation, such computer-readable media cancomprise a random-access memory (RAM), a read-only memory (ROM), anelectrically erasable programmable ROM (EEPROM), compact disk ROM(CD-ROM) or other optical disk storage, magnetic disk storage or othermagnetic storage devices, combinations of the aforementioned types ofcomputer-readable media, or any other medium that can be used to storecomputer executable code in the form of instructions or data structuresthat can be accessed by a computer.

An access point (“AP”) may comprise, be implemented as, or known as aNodeB, a Radio Network Controller (“RNC”), an eNodeB (eNB), a BaseStation Controller (“BSC”), a Base Transceiver Station (“BTS”), a BaseStation (“BS”), a Transceiver Function (“TF”), a Radio Router, a RadioTransceiver, a Basic Service Set (“BSS”), an Extended Service Set(“ESS”), a Radio Base Station (“RBS”), a Node B (NB), a gNB, a 5G NB, a5G BS, a Transmit Receive Point (TRP), or some other terminology.

An access terminal (“AT”) may comprise, be implemented as, or be knownas an access terminal, a subscriber station, a subscriber unit, a mobilestation, a remote station, a remote terminal, a user terminal, a useragent, a user device, user equipment (UE), a user station, a wirelessnode, or some other terminology. In some aspects, an access terminal maycomprise a cellular telephone, a smart phone, a cordless telephone, aSession Initiation Protocol (“SIP”) phone, a wireless local loop (“WLL”)station, a personal digital assistant (“PDA”), a tablet, a netbook, asmartbook, an ultrabook, a handheld device having wireless connectioncapability, a Station (“STA”), or some other suitable processing deviceconnected to a wireless modem. Accordingly, one or more aspects taughtherein may be incorporated into a phone (e.g., a cellular phone, a smartphone), a computer (e.g., a desktop), a portable communication device, aportable computing device (e.g., a laptop, a personal data assistant, atablet, a netbook, a smartbook, an ultrabook), wearable device (e.g.,smart watch, smart glasses, smart bracelet, smart wristband, smart ring,smart clothing, and/or the like), medical devices or equipment,biometric sensors/devices, an entertainment device (e.g., music device,video device, satellite radio, gaming device, and/or the like), avehicular component or sensor, smart meters/sensors, industrialmanufacturing equipment, a global positioning system device, or anyother suitable device that is configured to communicate via a wirelessor wired medium. In some aspects, the node is a wireless node. Awireless node may provide, for example, connectivity for or to a network(e.g., a wide area network such as the Internet or a cellular network)via a wired or wireless communication link. Some UEs may be consideredmachine-type communication (MTC) UEs, which may include remote devicesthat may communicate with a base station, another remote device, or someother entity. Machine type communications (MTC) may refer tocommunication involving at least one remote device on at least one endof the communication and may include forms of data communication whichinvolve one or more entities that do not necessarily need humaninteraction. MTC UEs may include UEs that are capable of MTCcommunications with MTC servers and/or other MTC devices through PublicLand Mobile Networks (PLMN), for example. Examples of MTC devicesinclude sensors, meters, location tags, monitors, drones, robots/roboticdevices, and/or the like. MTC UEs, as well as other types of UEs, may beimplemented as NB-IoT (narrowband internet of things) devices, enhancedMTC (eMTC) devices, LTE category M1 (LTE-M) devices, machine to machine(M2M) devices, and/or the like.

It is noted that while aspects may be described herein using terminologycommonly associated with 3G and/or 4G wireless technologies, aspects ofthe present disclosure can be applied in other generation-basedcommunication systems, such as 5G and later, including 5G technologies.

FIG. 1 is a diagram illustrating a network 100 in which aspects of thepresent disclosure may be practiced. The network 100 may be an LTEnetwork or some other wireless network, such as a 5G network. Wirelessnetwork 100 may include a number of BSs 110 (shown as BS 110 a, BS 110b, BS 110 c, and BS 110 d) and other network entities. A BS is an entitythat communicates with user equipment (UEs) and may also be referred toas a base station, a 5G BS, a Node B, a gNB, a 5G NB, an access point, aTRP, and/or the like. Each BS may provide communication coverage for aparticular geographic area. In 3GPP, the term “cell” can refer to acoverage area of a BS and/or a BS subsystem serving this coverage area,depending on the context in which the term is used.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or another type of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a closed subscriber group (CSG)). A BS for a macro cell may bereferred to as a macro BS. A BS for a pico cell may be referred to as apico BS. A BS for a femto cell may be referred to as a femto BS or ahome BS. In the example shown in FIG. 1, a BS 110 a may be a macro BSfor a macro cell 102 a, a BS 110 b may be a pico BS for a pico cell 102b, and a BS 110 c may be a femto BS for a femto cell 102 c. A BS maysupport one or multiple (e.g., three) cells. The terms “eNB”, “basestation”, “5G BS”, “gNB”, “TRP”, “AP”, “node B”, “5G NB”, and “cell” maybe used interchangeably herein.

In some examples, a cell may not necessarily be stationary, and thegeographic area of the cell may move according to the location of amobile BS. In some examples, the BSs may be interconnected to oneanother and/or to one or more other BSs or network nodes (not shown) inthe access network 100 through various types of backhaul interfaces suchas a direct physical connection, a virtual network, and/or the likeusing any suitable transport network.

Wireless network 100 may also include relay stations. A relay station isan entity that can receive a transmission of data from an upstreamstation (e.g., a BS or a UE) and send a transmission of the data to adownstream station (e.g., a UE or a BS). A relay station may also be aUE that can relay transmissions for other UEs. In the example shown inFIG. 1, a relay station 110 d may communicate with macro BS 110 a and aUE 120 d in order to facilitate communication between BS 110 a and UE120 d. A relay station may also be referred to as a relay BS, a relaybase station, a relay, and/or the like.

Wireless network 100 may be a heterogeneous network that includes BSs ofdifferent types, e.g., macro BSs, pico BSs, femto BSs, relay BSs, and/orthe like. These different types of BSs may have different transmit powerlevels, different coverage areas, and different impact on interferencein wireless network 100. For example, macro BSs may have a high transmitpower level (e.g., 5 to 40 Watts) whereas pico BSs, femto BSs, and relayBSs may have lower transmit power levels (e.g., 0.1 to 2 Watts).

A network controller 130 may couple to a set of BSs and may providecoordination and control for these BSs. Network controller 130 maycommunicate with the BSs via a backhaul. The BSs may also communicatewith one another, e.g., directly or indirectly via a wireless orwireline backhaul.

UEs 120 (e.g., 120 a, 120 b, 120 c) may be dispersed throughout wirelessnetwork 100, and each UE may be stationary or mobile. A UE may also bereferred to as an access terminal, a terminal, a mobile station, asubscriber unit, a station, and/or the like. A UE may be a cellularphone (e.g., a smart phone), a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, alaptop computer, a cordless phone, a wireless local loop (WLL) station,a tablet, a camera, a gaming device, a netbook, a smartbook, anultrabook, medical device or equipment, biometric sensors/devices,wearable devices (smart watches, smart clothing, smart glasses, smartwrist bands, smart jewelry (e.g., smart ring, smart bracelet)), anentertainment device (e.g., a music or video device, or a satelliteradio), a vehicular component or sensor, smart meters/sensors,industrial manufacturing equipment, a global positioning system device,or any other suitable device that is configured to communicate via awireless or wired medium. Some UEs may be considered evolved or enhancedmachine-type communication (eMTC) UEs. MTC and eMTC UEs include, forexample, robots, drones, remote devices, such as sensors, meters,monitors, location tags, and/or the like, that may communicate with abase station, another device (e.g., remote device), or some otherentity. A wireless node may provide, for example, connectivity for or toa network (e.g., a wide area network such as Internet or a cellularnetwork) via a wired or wireless communication link. Some UEs may beconsidered Internet-of-Things (IoT) devices. Some UEs may be considereda Customer Premises Equipment (CPE).

In FIG. 1, a solid line with double arrows indicates desiredtransmissions between a UE and a serving BS, which is a BS designated toserve the UE on the downlink and/or uplink. A dashed line with doublearrows indicates potentially interfering transmissions between a UE anda BS.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular RAT andmay operate on one or more frequencies. A RAT may also be referred to asa radio technology, an air interface, and/or the like. A frequency mayalso be referred to as a carrier, a frequency channel, and/or the like.Each frequency may support a single RAT in a given geographic area inorder to avoid interference between wireless networks of different RATs.In some cases, 5G RAT networks may be deployed.

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a base station) allocates resources forcommunication among some or all devices and equipment within thescheduling entity's service area or cell. Within the present disclosure,as discussed further below, the scheduling entity may be responsible forscheduling, assigning, reconfiguring, and releasing resources for one ormore subordinate entities. That is, for scheduled communication,subordinate entities utilize resources allocated by the schedulingentity.

Base stations are not the only entities that may function as ascheduling entity. That is, in some examples, a UE may function as ascheduling entity, scheduling resources for one or more subordinateentities (e.g., one or more other UEs). In this example, the UE isfunctioning as a scheduling entity, and other UEs utilize resourcesscheduled by the UE for wireless communication. A UE may function as ascheduling entity in a peer-to-peer (P2P) network, and/or in a meshnetwork. In a mesh network example, UEs may optionally communicatedirectly with one another in addition to communicating with thescheduling entity.

Thus, in a wireless communication network with a scheduled access totime-frequency resources and having a cellular configuration, a P2Pconfiguration, and a mesh configuration, a scheduling entity and one ormore subordinate entities may communicate utilizing the scheduledresources.

Techniques described herein use a wakeup signal to indicate to a UE 120whether an upcoming control channel signal resource includes informationrelevant to the UE 120. In this way, the UE 120 wakes up to performcomplex control channel signal processing only when the control channelincludes signals relevant to the UE 120, thereby conserving batterypower and resources of the UE 120. Such techniques are particularlysuited to MTC UEs 120, NB-IoT UEs 120, and/or the like, which maycommunicate with a network only occasionally, and which may be locatedin remote locations where changing or recharging a battery is difficult.

As indicated above, FIG. 1 is provided merely as an example. Otherexamples are possible and may differ from what was described with regardto FIG. 1.

FIG. 2 shows a block diagram 200 of a design of base station 110 and UE120, which may be one of the base stations and one of the UEs in FIG. 1.Base station 110 may be equipped with T antennas 234 a through 234 t,and UE 120 may be equipped with R antennas 252 a through 252 r, where ingeneral T≥1 and R≥1.

At base station 110, a transmit processor 220 may receive data from adata source 212 for one or more UEs, select one or more modulation andcoding schemes (MCS) for each UE based at least in part on channelquality indicators (CQIs) received from the UE, process (e.g., encodeand modulate) the data for each UE based at least in part on the MCS(s)selected for the UE, and provide data symbols for all UEs. Transmitprocessor 220 may also process system information (e.g., for semi-staticresource partitioning information (SRPI), and/or the like) and controlinformation (e.g., CQI requests, grants, upper layer signaling, and/orthe like) and provide overhead symbols and control symbols. Transmitprocessor 220 may also generate reference symbols for reference signals(e.g., the CRS) and synchronization signals (e.g., the primarysynchronization signal (PSS) and secondary synchronization signal(SSS)). A transmit (TX) multiple-input multiple-output (MIMO) processor230 may perform spatial processing (e.g., precoding) on the datasymbols, the control symbols, the overhead symbols, and/or the referencesymbols, if applicable, and may provide T output symbol streams to Tmodulators (MODs) 232 a through 232 t. Each modulator 232 may process arespective output symbol stream (e.g., for OFDM and/or the like) toobtain an output sample stream. Each modulator 232 may further process(e.g., convert to analog, amplify, filter, and upconvert) the outputsample stream to obtain a downlink signal. T downlink signals frommodulators 232 a through 232 t may be transmitted via T antennas 234 athrough 234 t, respectively. According to certain aspects described inmore detail below, the synchronization signals can be generated withlocation encoding to convey additional information.

At UE 120, antennas 252 a through 252 r may receive the downlink signalsfrom base station 110 and/or other base stations and may providereceived signals to demodulators (DEMODs) 254 a through 254 r,respectively. Each demodulator 254 may condition (e.g., filter, amplify,downconvert, and digitize) a received signal to obtain input samples.Each demodulator 254 may further process the input samples (e.g., forOFDM and/or the like) to obtain received symbols. A MIMO detector 256may obtain received symbols from all R demodulators 254 a through 254 r,perform MIMO detection on the received symbols if applicable, andprovide detected symbols. A receive (RX) processor 258 may process(e.g., demodulate and decode) the detected symbols, provide decoded datafor UE 120 to a data sink 260, and provide decoded control informationand system information to a controller/processor 280. A channelprocessor may determine RSRP, RSSI, RSRQ, CQI, and/or the like.

On the uplink, at UE 120, a transmit processor 264 may receive andprocess data from a data source 262 and control information (e.g., forreports comprising RSRP, RSSI, RSRQ, CQI, and/or the like) fromcontroller/processor 280. Transmit processor 264 may also generatereference symbols for one or more reference signals. The symbols fromtransmit processor 264 may be precoded by a TX MIMO processor 266 ifapplicable, further processed by modulators 254 a through 254 r (e.g.,for DFT-s-OFDM, CP-OFDM, and/or the like), and transmitted to basestation 110. At base station 110, the uplink signals from UE 120 andother UEs may be received by antennas 234, processed by demodulators232, detected by a MIMO detector 236 if applicable, and furtherprocessed by a receive (RX) processor 238 to obtain decoded data andcontrol information sent by UE 120. RX processor 238 may provide thedecoded data to a data sink 239 and the decoded control information tocontroller/processor 240. Base station 110 may include communicationunit 244 and communicate to network controller 130 via communicationunit 244. Network controller 130 may include communication unit 294,controller/processor 290, and memory 292.

Controllers/processors 240 and 280 and/or any other component(s) in FIG.2 may direct the operation at base station 110 and UE 120, respectively,to perform control channel monitoring using a wakeup signal. Forexample, controller/processor 280 and/or other processors and modules atbase station 110, may perform or direct operations of UE 120 to performcontrol channel monitoring using a wakeup signal. For example,controller/processor 280 and/or other controllers/processors and modulesat BS 110 may perform or direct operations of, for example, method 1100of FIG. 11, method 1200 of FIG. 12, and/or other processes as describedherein. In some aspects, one or more of the components shown in FIG. 2may be employed to perform example method 1100 of FIG. 11, method 1200of FIG. 12, and/or other processes for the techniques described herein.Memories 242 and 282 may store data and program codes for BS 110 and UE120, respectively. A scheduler 246 may schedule UEs for datatransmission on the downlink and/or uplink.

As indicated above, FIG. 2 is provided merely as an example. Otherexamples are possible and may differ from what was described with regardto FIG. 2.

FIG. 3 shows an example frame structure 300 for FDD in atelecommunications system (e.g., LTE). The transmission timeline foreach of the downlink and uplink may be partitioned into units of radioframes. Each radio frame may have a predetermined duration (e.g., 10milliseconds (ms)) and may be partitioned into 10 subframes with indicesof 0 through 9. Each subframe may include two slots. Each radio framemay thus include 20 slots with indices of 0 through 19. Each slot mayinclude L symbol periods, e.g., seven symbol periods for a normal cyclicprefix (as shown in FIG. 3) or six symbol periods for an extended cyclicprefix. The 2L symbol periods in each subframe may be assigned indicesof 0 through 2L−1.

While some techniques are described herein in connection with frames,subframes, slots, and/or the like, these techniques may equally apply toother types of wireless communication structures, which may be referredto using terms other than “frame,” “subframe,” “slot,” and/or the likein 5G. In some aspects, a wireless communication structure may refer toa periodic time-bounded communication unit defined by a wirelesscommunication standard and/or protocol.

In certain telecommunications (e.g., LTE), a BS may transmit a primarysynchronization signal (PSS) and a secondary synchronization signal(SSS) on the downlink in the center of the system bandwidth for eachcell supported by the BS. The PSS and SSS may be transmitted in symbolperiods 6 and 5, respectively, in subframes 0 and 5 of each radio framewith the normal cyclic prefix, as shown in FIG. 3. The PSS and SSS maybe used by UEs for cell search and acquisition. The BS may transmit acell-specific reference signal (CRS) across the system bandwidth foreach cell supported by the BS. The CRS may be transmitted in certainsymbol periods of each subframe and may be used by the UEs to performchannel estimation, channel quality measurement, and/or other functions.The BS may also transmit a physical broadcast channel (PBCH) in symbolperiods 0 to 3 in slot 1 of certain radio frames. The PBCH may carrysome system information. The BS may transmit other system informationsuch as system information blocks (SIBs) on a physical downlink sharedchannel (PDSCH) in certain subframes. The BS may transmit controlinformation/data on a physical downlink control channel (PDCCH) in thefirst B symbol periods of a subframe, where B may be configurable foreach subframe. The BS may transmit traffic data and/or other data on thePDSCH in the remaining symbol periods of each subframe. In some aspects,a wakeup signal may indicate whether the control information/data on thePDCCH is relevant to a UE.

In other systems (e.g., such as 5G systems), a Node B may transmit theseor other signals in these locations or in different locations of thesubframe.

As indicated above, FIG. 3 is provided merely as an example. Otherexamples are possible and may differ from what was described with regardto FIG. 3.

FIG. 4 shows two example subframe formats 410 and 420 with the normalcyclic prefix. The available time frequency resources may be partitionedinto resource blocks. Each resource block may cover 12 subcarriers inone slot and may include a number of resource elements. Each resourceelement may cover one subcarrier in one symbol period and may be used tosend one modulation symbol, which may be a real or complex value.

Subframe format 410 may be used for two antennas. A CRS may betransmitted from antennas 0 and 1 in symbol periods 0, 4, 7 and 11. Areference signal is a signal that is known a priori by a transmitter anda receiver and may also be referred to as pilot. A CRS is a referencesignal that is specific for a cell, e.g., generated based at least inpart on a cell identity (ID). In FIG. 4, for a given resource elementwith label Ra, a modulation symbol may be transmitted on that resourceelement from antenna a, and no modulation symbols may be transmitted onthat resource element from other antennas. Subframe format 420 may beused with four antennas. A CRS may be transmitted from antennas 0 and 1in symbol periods 0, 4, 7 and 11 and from antennas 2 and 3 in symbolperiods 1 and 8. For both subframe formats 410 and 420, a CRS may betransmitted on evenly spaced subcarriers, which may be determined basedat least in part on cell ID. CRSs may be transmitted on the same ordifferent subcarriers, depending on their cell IDs. For both subframeformats 410 and 420, resource elements not used for the CRS may be usedto transmit data (e.g., traffic data, control data, and/or other data).

The PSS, SSS, CRS and PBCH in LTE are described in 3GPP TS 36.211,entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); PhysicalChannels and Modulation,” which is publicly available.

An interlace structure may be used for each of the downlink and uplinkfor FDD in certain telecommunications systems (e.g., LTE). For example,Q interlaces with indices of 0 through Q−1 may be defined, where Q maybe equal to 4, 6, 8, 10, or some other value. Each interlace may includesubframes that are spaced apart by Q frames. In particular, interlace qmay include subframes q, q+Q, q+2Q, and/or the like, where q∈{0, . . . mQ−1}.

The wireless network may support hybrid automatic retransmission request(HARQ) for data transmission on the downlink and uplink. For HARQ, atransmitter (e.g., a BS) may send one or more transmissions of a packetuntil the packet is decoded correctly by a receiver (e.g., a UE) or someother termination condition is encountered. For synchronous HARQ, alltransmissions of the packet may be sent in subframes of a singleinterlace. For asynchronous HARQ, each transmission of the packet may besent in any subframe.

A UE may be located within the coverage of multiple BSs. One of theseBSs may be selected to serve the UE. The serving BS may be selectedbased at least in part on various criteria such as received signalstrength, received signal quality, path loss, and/or the like. Receivedsignal quality may be quantified by a signal-to-noise-and-interferenceratio (SINR), or a reference signal received quality (RSRQ), or someother metric. The UE may operate in a dominant interference scenario inwhich the UE may observe high interference from one or more interferingBSs.

While aspects of the examples described herein may be associated withLTE technologies, aspects of the present disclosure may be applicablewith other wireless communication systems, such as 5G technologies.

5G may refer to radios configured to operate according to a new airinterface (e.g., other than Orthogonal Frequency Divisional MultipleAccess (OFDMA)-based air interfaces) or fixed transport layer (e.g.,other than Internet Protocol (IP)). In aspects, 5G may utilize OFDM witha CP (herein referred to as cyclic prefix OFDM or CP-OFDM) and/or SC-FDMon the uplink, may utilize CP-OFDM on the downlink and include supportfor half-duplex operation using TDD. In aspects, 5G may, for example,utilize OFDM with a CP (herein referred to as CP-OFDM) and/or discreteFourier transform spread orthogonal frequency-division multiplexing(DFT-s-OFDM) on the uplink, may utilize CP-OFDM on the downlink andinclude support for half-duplex operation using TDD. 5G may includeEnhanced Mobile Broadband (eMBB) service targeting wide bandwidth (e.g.,80 megahertz (MHz) and beyond), millimeter wave (mmW) targeting highcarrier frequency (e.g., 60 gigahertz (GHz)), massive MTC (mMTC)targeting non-backward compatible MTC techniques, and/or missioncritical targeting ultra reliable low latency communications (URLLC)service.

A single component carrier bandwidth of 100 MHZ may be supported. 5Gresource blocks may span 12 sub-carriers with a sub-carrier bandwidth of75 kilohertz (kHz) over a 0.1 ms duration. Each radio frame may include50 subframes with a length of 10 ms. Consequently, each subframe mayhave a length of 0.2 ms. Each subframe may indicate a link direction(e.g., DL or UL) for data transmission and the link direction for eachsubframe may be dynamically switched. Each subframe may include DL/ULdata as well as DL/UL control data. UL and DL subframes for 5G may be asdescribed in more detail below with respect to FIGS. 7 and 8, and mayinclude control channel search space resources that map to wakeup signalresources, as described in more detail elsewhere herein.

Beamforming may be supported and beam direction may be dynamicallyconfigured. MIMO transmissions with precoding may also be supported.MIMO configurations in the DL may support up to 8 transmit antennas withmulti-layer DL transmissions up to 8 streams and up to 2 streams per UE.Multi-layer transmissions with up to 2 streams per UE may be supported.Aggregation of multiple cells may be supported with up to 8 servingcells. Alternatively, 5G may support a different air interface, otherthan an OFDM-based interface. 5G networks may include entities suchcentral units or distributed units.

The RAN may include a central unit (CU) and distributed units (DUs). A5G BS (e.g., gNB, 5G Node B, Node B, transmit receive point (TRP),access point (AP)) may correspond to one or multiple BSs. 5G cells canbe configured as access cells (ACells) or data only cells (DCells). Forexample, the RAN (e.g., a central unit or distributed unit) canconfigure the cells. DCells may be cells used for carrier aggregation ordual connectivity, but not used for initial access, cellselection/reselection, or handover. In some cases, DCells may nottransmit synchronization signals—in some case cases DCells may transmitSS. 5G BSs may transmit downlink signals to UEs indicating the celltype. Based at least in part on the cell type indication, the UE maycommunicate with the 5G BS. For example, the UE may determine 5G BSs toconsider for cell selection, access, handover, and/or measurement basedat least in part on the indicated cell type.

As indicated above, FIG. 4 is provided merely as an example. Otherexamples are possible and may differ from what was described with regardto FIG. 4.

FIG. 5 illustrates an example logical architecture of a distributed RAN500, according to aspects of the present disclosure. A 5G access node506 may include an access node controller (ANC) 502. The ANC may be acentral unit (CU) of the distributed RAN 500. The backhaul interface tothe next generation core network (NG-CN) 504 may terminate at the ANC.The backhaul interface to neighboring next generation access nodes(NG-ANs) may terminate at the ANC. The ANC may include one or more TRPs508 (which may also be referred to as BSs, 5G BSs, Node Bs, 5G NBs, APs,gNB, or some other term). As described above, a TRP may be usedinterchangeably with “cell.”

The TRPs 508 may be a distributed unit (DU). The TRPs may be connectedto one ANC (ANC 502) or more than one ANC (not illustrated). Forexample, for RAN sharing, radio as a service (RaaS), and servicespecific AND deployments, the TRP may be connected to more than one ANC.A TRP may include one or more antenna ports. The TRPs may be configuredto individually (e.g., dynamic selection) or jointly (e.g., jointtransmission) serve traffic to a UE.

The local architecture of RAN 500 may be used to illustrate fronthauldefinition. The architecture may be defined that support fronthaulingsolutions across different deployment types. For example, thearchitecture may be based at least in part on transmit networkcapabilities (e.g., bandwidth, latency, and/or jitter).

The architecture may share features and/or components with LTE.According to aspects, the next generation AN (NG-AN) 510 may supportdual connectivity with 5G. The NG-AN may share a common fronthaul forLTE and 5G.

The architecture may enable cooperation between and among TRPs 508. Forexample, cooperation may be preset within a TRP and/or across TRPs viathe ANC 502. According to aspects, no inter-TRP interface may beneeded/present.

According to aspects, a dynamic configuration of split logical functionsmay be present within the architecture of RAN 500. The PDCP, RLC, MACprotocol may be adaptably placed at the ANC or TRP.

According to certain aspects, a BS may include a central unit (CU)(e.g., ANC 502) and/or one or more distributed units (e.g., one or moreTRPs 508). Such BS may transmit wakeup signals to a UE, as described inmore detail elsewhere herein.

As indicated above, FIG. 5 is provided merely as an example. Otherexamples are possible and may differ from what was described with regardto FIG. 5.

FIG. 6 illustrates an example physical architecture of a distributed RAN600, according to aspects of the present disclosure. A centralized corenetwork unit (C-CU) 602 may host core network functions. The C-CU may becentrally deployed. C-CU functionality may be offloaded (e.g., toadvanced wireless services (AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 604 may host one or more ANC functions.Optionally, the C-RU may host core network functions locally. The C-RUmay have distributed deployment. The C-RU may be closer to the networkedge.

A distributed unit (DU) 606 may host one or more TRPs. The DU may belocated at edges of the network with radio frequency (RF) functionality.

As indicated above, FIG. 6 is provided merely as an example. Otherexamples are possible and may differ from what was described with regardto FIG. 6.

FIG. 7 is a diagram 700 showing an example of a DL-centric subframe orwireless communication structure. The DL-centric subframe may include acontrol portion 702. The control portion 702 may exist in the initial orbeginning portion of the DL-centric subframe. The control portion 702may include various scheduling information and/or control informationcorresponding to various portions of the DL-centric subframe. In someconfigurations, the control portion 702 may be a physical DL controlchannel (PDCCH), as indicated in FIG. 7. In some aspects, a wakeupsignal may indicate whether the PDCCH includes information relevant to aUE, and may be received prior to the PDCCH in time (e.g., in a previoussubframe or earlier in the same subframe).

The DL-centric subframe may also include a DL data portion 704. The DLdata portion 704 may sometimes be referred to as the payload of theDL-centric subframe. The DL data portion 704 may include thecommunication resources utilized to communicate DL data from thescheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE).In some configurations, the DL data portion 704 may be a physical DLshared channel (PDSCH).

The DL-centric subframe may also include an UL short burst portion 706.The UL short burst portion 706 may sometimes be referred to as an ULburst, an UL burst portion, a common UL burst, a short burst, an ULshort burst, a common UL short burst, a common UL short burst portion,and/or various other suitable terms. In some aspects, the UL short burstportion 706 may include one or more reference signals. Additionally, oralternatively, the UL short burst portion 706 may include feedbackinformation corresponding to various other portions of the DL-centricsubframe. For example, the UL short burst portion 706 may includefeedback information corresponding to the control portion 702 and/or thedata portion 704. Non-limiting examples of information that may beincluded in the UL short burst portion 706 include an ACK signal (e.g.,a PUCCH ACK, a PUSCH ACK, an immediate ACK), a NACK signal (e.g., aPUCCH NACK, a PUSCH NACK, an immediate NACK), a scheduling request (SR),a buffer status report (BSR), a HARQ indicator, a channel stateindication (CSI), a channel quality indicator (CQI), a soundingreference signal (SRS), a demodulation reference signal (DMRS), PUSCHdata, and/or various other suitable types of information. The UL shortburst portion 706 may include additional or alternative information,such as information pertaining to random access channel (RACH)procedures, scheduling requests, and various other suitable types ofinformation.

As illustrated in FIG. 7, the end of the DL data portion 704 may beseparated in time from the beginning of the UL short burst portion 706.This time separation may sometimes be referred to as a gap, a guardperiod, a guard interval, and/or various other suitable terms. Thisseparation provides time for the switch-over from DL communication(e.g., reception operation by the subordinate entity (e.g., UE)) to ULcommunication (e.g., transmission by the subordinate entity (e.g., UE)).The foregoing is merely one example of a DL-centric wirelesscommunication structure, and alternative structures having similarfeatures may exist without necessarily deviating from the aspectsdescribed herein.

As indicated above, FIG. 7 is provided merely as an example. Otherexamples are possible and may differ from what was described with regardto FIG. 7.

FIG. 8 is a diagram 800 showing an example of an UL-centric subframe orwireless communication structure. The UL-centric subframe may include acontrol portion 802. The control portion 802 may exist in the initial orbeginning portion of the UL-centric subframe. The control portion 802 inFIG. 8 may be similar to the control portion 702 described above withreference to FIG. 7. In some configurations, the control portion 802 maybe a physical DL control channel (PDCCH). In some aspects, a wakeupsignal may indicate whether the PDCCH includes information relevant to aUE, and may be received prior to the PDCCH in time (e.g., in a previoussubframe or earlier in the same subframe).

The UL-centric subframe may also include an UL long burst portion 804.The UL long burst portion 804 may sometimes be referred to as thepayload of the UL-centric subframe. The UL portion may refer to thecommunication resources utilized to communicate UL data from thesubordinate entity (e.g., UE) to the scheduling entity (e.g., UE or BS).

As illustrated in FIG. 8, the end of the control portion 802 may beseparated in time from the beginning of the UL long burst portion 804.This time separation may sometimes be referred to as a gap, guardperiod, guard interval, and/or various other suitable terms. Thisseparation provides time for the switch-over from DL communication(e.g., reception operation by the scheduling entity) to UL communication(e.g., transmission by the scheduling entity).

The UL-centric subframe may also include an UL short burst portion 806.The UL short burst portion 806 in FIG. 8 may be similar to the UL shortburst portion 706 described above with reference to FIG. 7, and mayinclude any of the information described above in connection with FIG.7. The foregoing is merely one example of an UL-centric wirelesscommunication structure and alternative structures having similarfeatures may exist without necessarily deviating from the aspectsdescribed herein.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet of Everything (IoE) communications, IoTcommunications, mission-critical mesh, and/or various other suitableapplications. Generally, a sidelink signal may refer to a signalcommunicated from one subordinate entity (e.g., UE1) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some examples, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

In one example, a wireless communication structure, such as a frame, mayinclude both UL-centric subframes and DL-centric subframes. In thisexample, the ratio of UL-centric subframes to DL-centric subframes in aframe may be dynamically adjusted based at least in part on the amountof UL data and the amount of DL data that are transmitted. For example,if there is more UL data, then the ratio of UL-centric subframes toDL-centric subframes may be increased. Conversely, if there is more DLdata, then the ratio of UL-centric subframes to DL-centric subframes maybe decreased.

As indicated above, FIG. 8 is provided merely as an example. Otherexamples are possible and may differ from what was described with regardto FIG. 8.

When in an idle mode or a connected mode discontinuous reception (CDRX)mode, a UE may enter a low power state to conserve battery power, andmay periodically wake up to monitor a control channel (e.g., the PDCCHand/or the like) for signals relating to the UE, such as pages. However,such control channel monitoring may be resource intensive and mayconsume battery power because the control channel uses complex signalsthat include a large amount of information. For example, the UE may wakeup, search for signals on the control channel, decode the signals if thesignals are found, and determine whether the decoded signals arerelevant to the UE. If the decoded control channel signals are notrelevant to the UE or no control channel signals are detected, then thebattery power used to search for, receive, and decode the controlchannel signals is wasted.

Techniques described herein use a simple (e.g., one bit) wakeup signalto indicate to the UE whether an upcoming control channel signalresource includes information relevant to the UE. In this way, the UEwakes up to perform complex control channel signal processing only whenthe control channel includes signals relevant to the UE, therebyconserving battery power and resources of the UE. Such techniques areparticularly suited to MTC UEs, NB-IoT UEs, and/or the like, which maycommunicate with a network only occasionally, and which may be locatedin remote locations where changing or recharging a battery is difficult.

FIG. 9 is a diagram illustrating an example 900 of control channelmonitoring using a wakeup signal. A wakeup signal may be communicatedfrom a base station to a UE to indicate whether an upcoming controlchannel search space resource (e.g., a control channel resource in thetime domain, the frequency domain, a code domain, and/or the like) willinclude information for the UE, such as a page, data, and/or the like.In some aspects, the UE may identify a wakeup signal resource associatedwith the UE based at least in part on a control channel search spaceresource associated with the UE. A wakeup signal resource may be definedin a time domain (e.g., using time division multiplexing), in afrequency domain (e.g., using frequency division multiplexing), in acode domain (e.g., using code division multiplexing, using a sequence),and/or the like. The wakeup signal resource may map to the controlchannel search space resource and may precede the control channel searchspace resource. In some aspects, the wakeup signal resource may be in asubframe (or slot) prior to a subframe (or slot) that includes thecontrol channel search space resource. In some aspects, the wakeupsignal resource may precede the control channel search space resource ina same subframe (or slot). In some aspects, a wakeup signal resource maymap to one or more control channel search space resources (e.g., on oneor more carriers, on one or more sets of subframes, and/or the like).

As shown in FIG. 9, a wakeup signal group 905 may include multiplewakeup signals in different resources (e.g., in the time domain, thefrequency domain, the code domain, and/or the like). For example, thewakeup signal group 905 may include a first wakeup signal subgroup 910(shown as WS Subgroup 1), a second wakeup signal subgroup 915 (shown asWS Subgroup 2), a third wakeup signal subgroup 920 (shown as WS Subgroup3), and/or the like. A wakeup signal subgroup may include one or morewakeup signals (e.g., shown as a first wakeup signal WS1 and a secondwakeup signal WS2). Additionally, or alternatively, the wakeup signalsubgroups 910, 915, 920 included in the wakeup signal group 905 may beconfigured with a periodicity and/or time offset, shown as a firstwakeup signal period 925 (e.g., WS Period 1), a second wakeup signalperiod 930 (e.g., WS Period 2), and a third wakeup signal period 935(e.g., WS Period 3). In some aspects, different wakeup signal groups maybe configured with different periodicities, time offsets, subgroup sizes(e.g., number of wakeup signals included in a subgroup), and/or thelike. Although the wakeup signal subgroups are shown as beingnon-overlapping in time, in some aspects, a first wakeup signal subgroupmay overlap in time with a second wakeup signal subgroup (e.g., asubsequent wakeup signal subgroup).

As further shown in FIG. 9, a first control channel search space (CCSS)period 940 may be controlled by the first wakeup signal subgroup 910, asecond CCSS period 945 may be controlled by the second wakeup signalsubgroup 915, and a third CCSS period 950 may be controlled by the thirdwakeup signal subgroup 920. When a CCSS resource begins in the firstCCSS period 940, as shown by reference number 955, a UE associated withthe CCSS resource may monitor a wakeup signal in the first wakeup signalsubgroup 910 for an indication of whether the CCSS resource includesinformation relevant to the UE. For example, the UE may identify a CCSSresource associated with the UE (e.g., as shown by reference number955), may identify a wakeup signal resource corresponding to the CCSSresource (e.g., the second wake up signal resource WS2 within the firstwakeup signal subgroup 910), and may monitor the wakeup signal resourcefor an indication of whether to monitor the CCSS resource. The UE mayselectively monitor the CCSS resource based at least in part on theindication. For example, the UE may initiate a wakeup procedure tomonitor the CCSS resource when the indication indicates that the CCSSresource is to be monitored, or may sleep during the CCSS resource whenthe indication indicates that the CCSS resource is not to be monitored.In this way, the UE may skip monitoring of a CCSS resource when the CCSSresource does not include information relevant to the UE, therebyconserving battery power and UE resources.

As shown, a first UE (e.g., UE 1) may be associated with one CCSSresource in the first CCSS period 940. The first UE may monitor a wakeupsignal in the first wakeup signal subgroup 910 to determine whether tomonitor the CCSS resource. For example, the first UE may monitor atleast one of WS1 or WS2 (e.g., depending on a configuration, asdescribed below). As further shown, a second UE (e.g., UE 2) may beassociated with two CCSS resources that begin in the first CCSS period940. In some aspects, the second UE may monitor a first wakeup signal inthe first wakeup signal subgroup 910 (e.g., WS1) to determine whether tomonitor the first CCSS resource, and may monitor a second wakeup signalin the first wakeup signal subgroup 910 (e.g., WS2) to determine whetherto monitor the second CCSS resource. In some aspects, the second UE maymonitor a single wakeup signal (e.g., WS1) to determine whether to wakeup for both the first CCSS resource and the second CCSS resource. Forexample, a single wakeup signal may correspond to multiple CCSSresources (e.g., indicated by a number of CCSS resources, a time periodassociated with one or more CCSS resources, and/or the like). In someaspects, the size of the wakeup signal subgroup may correspond to amaximum number of CCSS resources, associated with a single UE, thatoccur in a CCSS period. As further shown, a third UE (e.g., UE 3) isassociated with one CCSS resource in the first CCSS period 940, and maymonitor the first wakeup signal subgroup 910 in a similar manner asdescribed in connection with the first UE.

When a CCSS resource begins in the second CCSS period 945, as shown byreference number 960, a UE associated with the CCSS resource may monitora wakeup signal in the second wakeup signal subgroup 915 for anindication of whether the CCSS resource includes information relevant tothe UE. For example, the first UE and the second UE may monitor thesecond wakeup signal subgroup 915 in a similar manner as described abovein connection with the first wakeup signal subgroup 910. However, thethird UE is not associated with any CCSS resources in the second CCSSperiod 945. In this case, the third UE may skip monitoring of the secondwakeup signal subgroup 915, thereby further conserving battery power andUE resources. In some aspects, the UE(s) may receive indications from abase station that indicate the CCSS resources.

When a CCSS resource begins in the third CCSS period 950, as shown byreference number 965, a UE associated with the CCSS resource may monitora wakeup signal in the third wakeup signal subgroup 920 for anindication of whether the CCSS resource includes information relevant tothe UE. For example, the first UE, the second UE, and the third UE maymonitor the third wakeup signal subgroup 920 in a similar manner asdescribed above in connection with the first wakeup signal subgroup 910.

As shown by reference number 970, in some aspects, there may be a margin(e.g., a time margin) between the end of a wakeup signal subgroup andthe beginning of a CCSS period and/or a first CCSS resource that occursin the CCSS period. This margin may allow for sufficient time for thewakeup signal to be processed by one or more UEs prior to the occurrenceof a CCSS resource associated with the one or more UEs.

As further shown in FIG. 9, in some aspects, the wakeup signal subgroup(e.g., a location of the wakeup signal subgroup) may occur before acorresponding CCSS location of a UE with no intervening wakeup signalsubgroups associated with the UE. In this way, latency may be reducedand the UE and base station need not process data in advance as comparedto using a wakeup signal subgroup that occurs a longer time before theCCSS resource.

In some aspects, a wakeup signal resource may map to multiple CCSSresources. In some aspects, the multiple CCSS resources may beassociated with a single UE. For example, the first wakeup signalsubgroup 910 may map to two CCSS resources associated with the secondUE. Additionally, or alternatively, the multiple CCSS resources may beassociated with multiple UEs. For example, the first wakeup signalsubgroup 910 may map to one CCSS resource associated with the first UE,two CCSS resources associated with the second UE, and one CCSS resourceassociated with the third UE. In some aspects, a wakeup signal may beused to control monitoring of CCSS resources for multiple UEs, therebyconserving network resources as compared to using separate wakeupsignals for each UE.

In some aspects, a UE may identify a wakeup signal resourcecorresponding to a CCSS resource based at least in part on a periodicityor a time offset associated with the wakeup signal resource. Forexample, the wakeup signal resource may have a time offset compared to aboundary of a CCSS period, a boundary of a CCSS resource, and/or thelike. Furthermore, different wakeup signal resources may be separated intime according to a periodicity. In some aspects, the time offset and/orthe periodicity may be signaled to the UE by a base station.

In some aspects, a UE may be mapped to a wakeup signal group (e.g., oneor more wakeup signal resources) based at least in part on one or morefactors. In this case, a base station may transmit multiple wakeupsignals in different resources or groups, and may assign UEs to thedifferent resources or groups based at least in part on the one or morefactors. A factor may include, for example, a UE identifier associatedwith a UE, a radio network temporary identifier (RNTI) associated withcontrol channel communications monitored by a UE, a signal-to-noiseratio (SINR) associated with a UE, a maximum repetition level associatedwith a UE, an actual repetition level associated with control channelcommunications for the UE, a carrier index associated with a CCSSresource associated with the UE, and/or the like. In some aspects, if aUE identifier is used to assign UEs to wakeup signal groups, the bits ofthe UE identifier used for the assignment may be different from the bitsof the UE identifier used to assign UEs to paging groups (e.g., toreceive pages). In this way, the wakeup signal resource may be differentfor different UEs that monitor the same paging resource, therebyreducing false paging wakeups. In some aspects, if the UE monitorsmultiple RNTIs for the PDCCH, and the wakeup signal resource depends onthe RNTI, then the UE may monitor only one wakeup signal resource forall RNTIs monitored by the UE. In this case, the base station may send awakeup signal resource corresponding to one RNTI, but may send theactual PDCCH using a different RNTI. Alternatively, the UE may monitordifferent wakeup signal resources for different RNTIs.

In some aspects, such mapping of UEs to wakeup signal groups may improveperformance. For example, a first wakeup signal group may have a shortperiodicity, with wakeup signals being transmitted more often than asecond wakeup signal group with a long periodicity. In this case, thebase station may map UEs with low SINR (e.g., less than a threshold), ahigh repetition level for repeated communications (e.g., a maximum oractual repetition level that is greater than a threshold), and/or thelike, to the first wakeup signal group. In this way, UEs associated withpoor network conditions are more likely to receive a wakeup signalbecause of the lower periodicity. Conversely, the base station may mapUEs with high SINR (e.g., greater than a threshold), a low repetitionlevel for repeated communications (e.g., a maximum or actual repetitionlevel that is less than a threshold), and/or the like, to the secondwakeup signal group. In this way, UEs associated with good networkconditions may conserve battery power and UE resources because of thehigher periodicity.

In some aspects, the wakeup signal may be transmitted in a fixedresource, thereby reducing UE power needed to monitor the wakeup signal.In some aspects, the wakeup signal may be transmitted in multipleresources, and the UE may monitor the multiple resources, which mayincrease scheduling flexibility at the expense of UE power consumption.In some aspects, the wakeup signal may be transmitted using timediversity (e.g., by breaking the wakeup signal or multiple wakeupsignals into multiple chunks transmitted with intervening time gaps).For example, the wakeup signal may be transmitted using space frequencyblock coding (SFBC), space time transmit diversity (STTD), beamsweeping, and/or the like. Additionally, or alternatively, the wakeupsignal may be transmitted using frequency diversity (e.g., usingfrequency hopping for different wakeup signals).

As indicated above, FIG. 9 is provided as an example. Other examples arepossible and may differ from what was described with respect to FIG. 9.

FIG. 10 is a diagram illustrating another example 1000 of controlchannel monitoring using a wakeup signal. As described above inconnection with FIG. 9, a wakeup signal may be communicated from a basestation to a UE to indicate whether an upcoming CCSS resource (e.g., aPDCCH search space resource) will include information for the UE, suchas a page and/or the like. In some aspects, the UE may identify a wakeupsignal resource associated with the UE based at least in part on a CCSSresource associated with the UE. The wakeup signal resource may map tothe CCSS resource and may precede the control channel search spaceresource.

As shown by reference number 1005, in some aspects, a wakeup signalresource may occur at a preconfigured time period before a CCSSresource. The preconfigured time period may be, for example, a number ofsubframes (or slots) before the CCSS resource and/or the like. In thiscase, the UE may identify the wakeup signal resource based at least inpart on a corresponding CCSS resource and the number of subframes. Insome aspects, the base station may signal the preconfigured time period(e.g., the number of subframes) to the UE. Additionally, oralternatively, the preconfigured time period may be determined based atleast in part on at least one of a SINR associated with the UE, amaximum repetition level of the control channel associated with the UE,an actual repetition level associated with control channelcommunications for the UE, and/or the like. For example, a UE associatedwith a low SINR and/or a high repetition level may be configured to usea larger number of subframes between the wakeup signal resource and theCCSS resource to provide an opportunity for wakeup signal repetitionprior to the CCSS resource. Conversely, a UE associated with a high SINRand/or a low repetition level may be configured to use a smaller numberof subframes between the wakeup signal resource and the CCSS resourcebecause wakeup signal repetitions may not be necessary.

In some aspects, different UEs associated with a same CCSS resource maymonitor different wakeup signals included in a wakeup signal subgroupthat corresponds to the CCSS resource. For example, a first UE maymonitor a first wakeup signal in the wakeup signal subgroup to determinewhether to monitor the CCSS resource, and a second UE may monitor asecond wakeup signal in the wakeup signal subgroup to determine whetherto monitor the CCSS resource. In this way, network resources may beconserved by permitting multiple UEs to monitor the same wakeup signalsubgroup, rather than using different wakeup signal subgroups fordifferent UEs.

By using a wakeup signal resource that occurs a configurable number ofsubframes (or slots) before a corresponding CCSS resource, schedulingdelay can be reduced. For example, a base station may be able to makescheduling decisions for communications closer in time to when thecommunications are actually sent, thereby improving utilization ofnetwork resources during scheduling.

In some aspects, the base station may signal a wakeup signal mode to theUE, and/or the base station and the UE may negotiate a wakeup signalmode. In some aspects, a first wakeup signal mode may use a wakeupsignal subgroup to provide indications for CCSS resources included in aCCSS period, as described above in connection with FIG. 9. In someaspects, a second wakeup signal mode may use a wakeup signal prior toeach CCSS resource, with no intervening CCSS resources, as described inconnection with FIG. 10. In some aspects, the wakeup signal mode may bedetermined based at least in part on whether the wakeup signal is beingused for paging, CDRX, a particular type of RNTI, and/or the like. Insome aspects, both wakeup signal modes may be used together. Forexample, the first wakeup signal mode may be used for the first CCSSresource for a UE within a CCSS period, and the second wakeup signalmode may be used for additional CCSS resources for the UE within theCCSS period.

In some aspects, configuration information associated with wakeupsignaling may be included in a master information block, a systeminformation block, a unicast communication (e.g., in CDRX), and/or thelike. The configuration information may include, for example, aperiodicity, a number and/or configuration of wakeup signal groups, anumber and/or configuration of wakeup signal subgroups, a margin, and/orthe like.

In some aspects, the presence of a wakeup signal in a wakeup signalresource may indicate that a corresponding CCSS resource includesinformation relevant to a UE monitoring the wakeup signal. In this case,the UE may be configured to monitor the CCSS resource when a wakeupsignal is present in the wakeup signal resource. Additionally, oralternatively, the absence of a wakeup signal in a wakeup signalresource may indicate that a corresponding CCSS resource does notinclude information relevant to a UE monitoring the wakeup signal. Inthis case, the UE may be configured to skip monitoring of the CCSSresource when a wakeup signal is absent from the wakeup signal resource.In this way, a base station may prevent transmission of a wakeup signalwhen a corresponding CCSS resource does not include information relevantto the UE, thereby conserving network resources. In some aspects, thebase station may transmit multiple wakeup signals corresponding todifferent groups of UEs in a same time period, a same frequency, and/orthe like. Alternatively, the presence of a wakeup signal in a wakeupsignal resource may indicate that a corresponding CCSS resource does notinclude information relevant to a UE monitoring the wakeup signal, andthe absence of a wakeup signal in a wakeup signal resource may indicatethat a corresponding CCSS resource includes information relevant to a UEmonitoring the wakeup signal.

In some aspects, a first bit value in the wakeup signal (e.g., 1) mayindicate that the CCSS resource is to be monitored because the CCSSresource includes information relevant to the UE, and a second bit valuein the wakeup signal (e.g., 0) may indicate that the CCSS resource is tobe skipped because the CCSS resource does not include informationrelevant to the UE. In some aspects, a single bit may be used for thewakeup signal. In some aspects, multiple bits may be used for the wakeupsignal. In some aspects, a payload size (e.g., a number of bits) of thewakeup signal may be less than a number of bits used for legacy downlinkcontrol information (DCI). For example, a legacy DCI payload (e.g., aPDCCH payload) may be 23 bits (e.g., for NB-IoT devices), and thepayload size of the wakeup signal may be, for example, 1 bit, 2 bits, 3bits, 4 bits, 5 bits, and/or the like. Since the number of resources(e.g. subframes) to be monitored to decode the PDCCH increase with thenumber of payload bits, using a smaller payload would help reduce thenumber of monitored resources. In this way, the UE may save power bymonitoring fewer subframes or resource elements. In some aspects, DCIsent with the wakeup signal may be sent in a same search space as legacyDCI. In some aspects, DCI sent with the wakeup signal may be sent in anearlier search space than legacy DCI. In some aspects, DCI sent with thewakeup signal may be sent in a different search space than legacy DCI.

In some aspects, a value of the bit(s) may indicate a particular CCSSresource to be monitored when the wakeup signal corresponds to multipleCCSS resources. For example, a first value may indicate that the UE isto monitor only a first CCSS resource corresponding to the wakeupsignal, a second value may indicate that the UE is to monitor only asecond CCSS resource corresponding to the wakeup signal, a third valuemay indicate that the UE is to monitor both the first and second CCSSresources, a fourth value (or the absence of a wakeup signal) mayindicate that the UE is to skip monitoring of all corresponding CCSSresources, and/or the like.

In some aspects, one or more payload bits of the wakeup signal mayindicate at least one of whether to monitor a corresponding CCSSresource, one or more UEs (e.g., indicated by a UE identifier, a RNTI,and/or the like) that are to monitor the corresponding CCSS resource,one or more resources (e.g., a carrier, a search space, a subframe, aslot, a time resource, a frequency resource, and/or the like) where thecontrol channel is enabled, one or more parameters to be used to decodethe control channel (e.g., a bandwidth, a type of control channel,and/or the like), whether the UE is to transmit CSI feedback associatedwith monitoring the wakeup signal and/or the CCSS resource, and/or thelike. In some aspects, the control channel may be a PDCCH, an eMTCPDCCH, an NB-IoT PDCCH, a legacy PDCCH, an ePDCCH, and/or the like.

In some aspects, the wakeup signal resource may correspond to a numberof resource elements associated with a wakeup signal that is transmittedover a plurality of resource elements, and the number of resourceelements over which a UE is configured to monitor for the wakeup signalis determined based at least in part on a maximum repetition level ofcontrol channel communications or a signal-to-noise ratio associatedwith the UE. For example, a wakeup signal may be sent over multiplesubframes, and a UE may monitor a portion of the multiple subframes orall of the subframes. In some aspects, the number of subframes overwhich the wakeup signal is configured (e.g., the length of the wakeupsignal) may be based at least in part on (e.g., equal to) a maximumrepetition level for the control channel. In some aspects, a UEconfigured with the maximum repetition level supported by the system maymonitor all of the subframes. In some aspects, a UE configured with amaximum control channel repetition level that is less than the maximumrepetition level supported by the system may monitor less than all(e.g., a portion) of the subframes. In some aspects, the number ofsubframes and/or resource elements monitored by the UE may be a functionof a maximum control channel repetition level associated with the UEand/or a SINR associated with the UE. In this way, the UE may conservebattery power and UE resources when in good network conditions, and mayincrease a likelihood of receiving the wakeup signal when in poornetwork conditions. Additionally, or alternatively, a UE may beconfigured to identify or monitor the wakeup signal resource based atleast in part on a determination that the UE is associated with arepetition level or a signal-to-noise ratio that satisfies a condition.For example, wakeup signal monitoring may be enabled for a UE only whenthe UE is associated with poor network conditions.

In some aspects, a length of the wakeup signal (e.g., a number ofresource elements, subframes, bits, and/or the like used for the wakeupsignal) may be configured based at least in part on a maximum repetitionlevel and/or an actual repetition level associated with the controlchannel, as described above. Additionally, or alternatively, the lengthof the wakeup signal may be configured based at least in part on whetherthe wakeup signal is transmitted using transmit diversity (TxD), whetherthe wakeup signal is transmitted using frequency hopping, a DRX cyclelength associated with the UE and/or cell, and/or the like. For example,if the wakeup signal is transmitted using TxD, then the length of thewakeup signal (e.g., for a given SINR level) may be configured to beshorter than if the wakeup signal is not transmitted using TxD.Similarly, if the wakeup signal is transmitted using frequency hopping,then the length of the wakeup signal (e.g., for a given SINR level) maybe configured to be shorter than if the wakeup signal is not transmittedusing frequency hopping. In this way, the length of the wakeup signalmay be shorter to conserve network resources when the UE has a greaterlikelihood of receiving the wakeup signal as a result of TxD and/orfrequency hopping.

In some aspects, the wakeup signal may be configured to have a longerlength for a longer DRX cycle (e.g., greater than or equal to athreshold), and may be configured to have a shorter length for a shorterDRX cycle. As the length of the DRX cycle increases, the likelihood of atiming and/or frequency error increases, and so the wakeup signal may beconfigured with a longer length to increase the likelihood of receptionof the wakeup signal by the UE. Additionally, or alternatively, thelength of the wakeup signal may be explicitly configured (e.g.,signaled) via a radio resource control (RRC) configuration message.

In some aspects, to reduce a time duration of the wakeup signal andenable a UE sleep mode (e.g., micro sleep), the wakeup signal may betransmitted using a higher bandwidth (e.g., a maximum possible bandwidthor a power level corresponding to the maximum possible bandwidth). Forexample, for NB-IoT, the wakeup signal may be transmitted using a fullone resource block; for eMTC, the wakeup signal may be transmitted usinga full six resource blocks; and/or the like. Additionally, oralternatively, the wakeup signal may be transmitted with power boostingby using power of unused resource element(s) in symbol(s) in which thewakeup signal is transmitted, thus decreasing the bandwidth that the UEneeds to monitor. For example, for NB-IoT, the wakeup signal may betransmitted in two tones, but may use the power of the entire resourceblock so that the UE would effectively achieve the performance as 12resource elements, but will only monitor 2 resource elements.Additionally, or alternatively, the bandwidth used for the wakeup signal(e.g., a number of resource elements in the frequency domain) may beconfigurable. In some aspects, wakeup signal transmission may beconfigured to minimize a number of symbols for transmission beforereducing a number of frequencies used for transmission.

In some aspects, the UE may transmit an acknowledgement indication (ACK)in response to detecting the wakeup signal. In this way, the basestation may conserve resources by avoiding transmission on the PDCCHwhen an ACK is not received. In some aspects, the base station may relyon the ACK for the corresponding PDCCH communication. In some aspects,the base station may transmit multiple wakeup signals (e.g., in a DRX onduration, a paging occasion, and/or the like), and the UE may ACK themultiple wakeup signals. In some aspects, if the ACK if used in responseto the PDCCH communication, the base station may retransmit the wakeupsignal and the corresponding PDCCH communication if the ACK is notreceived. In this case, a DRX on duration may be increased to accountfor the multiple transmissions. In some aspects, the UE may sleepbetween consecutive wakeup signals and/or corresponding PDCCHcommunications to achieve power savings.

In some aspects, for NB-IoT, a wakeup signal may be sent on a differentcarrier than the PDCCH communication. Additionally, or alternatively,one wakeup signal resource may correspond to multiple PDCCH carriers,subframes, search spaces, and/or the like. In some aspects, thesubframes used for the wakeup signal on an NB-IoT carrier may be thesame subframes as those determined to be available for PDCCH and/orPDSCH communications on that carrier. In some aspects, an independentvalid subframe configuration (e.g., a bitmap) may be signaled for thewakeup signal resource on the NB-IoT carrier. In some aspects, thewakeup signal may be sent in a PDSCH region, and may occupy the entiresubframe (e.g., for standalone band and/or guard band), or may occupyonly a non-control portion of the subframe (e.g., for in-band).Alternatively, the wakeup signal may occupy the entire subframe for thestandalone and/or guard band. In some aspects, a narrowband referencesignal (NRS) may be present, and the wakeup signal may be rate matchedand/or punctured around the NRS. In some aspects, the UE may assume thepresence of NRS. In some aspects, the UE may assume the absence of NRS.In some aspects, the UE may receive an indication of whether NRS ispresent or absent in a wakeup signal resource (e.g., a same subframe asa wakeup signal), and may decode the wakeup signal based at least inpart on the indication. Additionally, or alternatively, the UE maydetermine whether the NRS is present or absent on a carrier based atleast in part on whether the carrier is an anchor carrier or anon-anchor carrier.

In some aspects, the UE may apply adaptive receive diversity (RxD) toreception of the wakeup signal and/or the corresponding PDCCHcommunication. For example, the UE may monitor the wakeup signal withoutRxD, and may monitor the corresponding PDCCH with RxD (e.g., to conservepower when monitoring the wakeup signal). Additionally, oralternatively, the UE may modify one or more parameters to enable ordisable RxD (e.g., after a number of received wakeup signals, after anumber of received PDCCH communications, after a number of pagingoccasions, after a number of PDCCH monitoring occasions, and/or thelike) based at least in part on whether a communication to be receivedis a wakeup signal, a corresponding PDCCH, and/or the like.

In some aspects, for a 20 MHz bandwidth, a 5 MHz PDCCH control regionmay be defined in the PDSCH so the UE can monitor a smaller bandwidth.In some aspects, multiple such 5 MHz legacy PDCCH regions may bedefined. In this case, legacy PDCCH multiplexing may be reused to enablereuse of UE hardware and/or the like. For example, a first set of OFDMsymbols may correspond to a first PDCCH control region that a UE willmonitor, a second set of OFDM symbols may correspond to a second PDCCHcontrol region for a different subframe, a different UE identifier,and/or the like.

As indicated above, FIG. 10 is provided as an example. Other examplesare possible and may differ from what was described with respect to FIG.10.

FIG. 11 is a flow chart of a method 1100 of wireless communication. Themethod may be performed by a UE (e.g., the UE 120 of FIG. 1, one or moreUEs described in connection with FIG. 9 and/or FIG. 10, the apparatus1302 of FIG. 13, the apparatus 1302′ of FIG. 14, and/or the like).

At 1110, the UE may identify a wakeup signal resource associated withthe UE. For example, the UE may identify a wakeup signal resourceassociated with the UE based at least in part on a control channelsearch space resource associated with the UE, as described above inconnection with FIGS. 9 and 10. The wakeup signal resource may map tothe control channel search space resource and may precede the controlchannel search space resource (e.g., in time).

In some aspects, the wakeup signal resource maps to a plurality ofcontrol channel search space resources. In some aspects, the pluralityof control channel search space resources are associated with the UE. Insome aspects, the plurality of control channel search space resourcesare associated with a plurality of UEs. In some aspects, a wakeup signalin the wakeup signal resource indicates one or more UEs that are tomonitor the control channel search space resource. In some aspects, thewakeup signal resource is different for different UEs monitoring thesame paging resource.

In some aspects, the wakeup signal resource is identified based at leastin part on a periodicity or a time offset associated with the wakeupsignal resource. In some aspects, the wakeup signal resource isidentified based at least in part on at least one of: a UE identifierassociated with the UE, a radio network temporary identifier (RNTI)associated with control channel communications monitored by the UE, asignal-to-noise ratio associated with the UE, a maximum repetition levelassociated with the UE, an actual repetition level associated withcontrol channel communications for the UE, a carrier index associatedwith the control channel search space resource, or some combinationthereof.

In some aspects, the wakeup signal resource occurs before the controlchannel search space resource with no intervening wakeup signalresources associated with the UE. In some aspects, the wakeup signalresource occurs a number of subframes before the control channel searchspace resource. In some aspects, the number of subframes is identifiedbased at least in part on at least one of: a signal-to-noise ratioassociated with the UE, a maximum repetition level associated with theUE, an actual repetition level associated with control channelcommunications for the UE, or some combination thereof.

In some aspects, the UE is configured to identify or monitor the wakeupsignal resource based at least in part on a determination that the UE isassociated with a repetition level or a signal-to-noise ratio thatsatisfies a condition.

At 1120, the UE may monitor the wakeup signal resource for an indicationof whether to monitor the control channel search space resource. Forexample, the UE may monitor the wakeup signal resource, which mayindicate whether to monitor the control channel search space resource,as described above in connection with FIGS. 9 and 10.

In some aspects, the UE is configured to monitor the control channelsearch space resource when a wakeup signal is present in the wakeupsignal resource. Additionally, or alternatively, the UE is configured toskip monitoring of the control channel search space resource when thewakeup signal is absent from the wakeup signal resource. In someaspects, the UE is configured to identify or monitor the wakeup signalresource based at least in part on a determination that the UE isassociated with a repetition level or a signal-to-noise ratio thatsatisfies a condition.

In some aspects, the wakeup signal resource corresponds to a number ofresource elements associated with a wakeup signal that is transmittedover a plurality of resource elements. In some aspects, the number ofresource elements over which the UE is configured to monitor for thewakeup signal is determined based at least in part on a maximumrepetition level of control channel communications or a signal-to-noiseratio associated with the UE. In some aspects, a length of the wakeupsignal is configured based at least in part on at least one of: amaximum repetition level associated with a control channel that includesthe control channel search space resource, an actual repetition levelassociated with the control channel, a determination of whether thewakeup signal is transmitted using transmit diversity, a determinationof whether the wakeup signal is transmitted using frequency hopping, adiscontinuous reception cycle length associated with the UE, a radioresource control (RRC) configuration message, or some combinationthereof. In some aspects, a payload size of a wakeup signal in thewakeup signal resource is less than a payload size used for legacydownlink control information in a control channel that includes thecontrol channel search space resource, wherein the wakeup signal is alsocarried on a physical downlink control channel (PDCCH).

In some aspects, the wakeup signal resource is identified or monitoredbased at least in part on a wakeup signal mode determined based at leastin part on whether a wakeup signal is being used for connected modediscontinuous reception (CDRX)

At 1130, the UE may selectively monitor the control channel search spaceresource based at least in part on the indication. For example, the UEmay selectively monitor (e.g., may monitor or skip monitoring) thecontrol channel search space resource based at least in part on theindication, in the wakeup signal resource, of whether to monitor thecontrol channel search space resource, as described above in connectionwith FIGS. 9 and 10.

In some aspects, the UE is configured to initiate a wakeup procedure tomonitor the control channel search space resource when the monitoring ofthe wakeup signal resource indicates that the control channel searchspace resource is to be monitored. Additionally, or alternatively, theUE is configured to sleep during the control channel search spaceresource when the monitoring of the wakeup signal resource indicatesthat the control channel search space resource is not to be monitored.

Although FIG. 11 shows example blocks of a method of wirelesscommunication, in some aspects, the method may include additionalblocks, fewer blocks, different blocks, or differently arranged blocksthan those shown in FIG. 11. Additionally, or alternatively, two or moreblocks shown in FIG. 11 may be performed in parallel.

FIG. 12 is a flow chart of a method 1200 of wireless communication. Themethod may be performed by a base station (e.g., the base station 110 ofFIG. 1, one or more base stations described in connection with FIG. 9and/or FIG. 10, the apparatus 1502 of FIG. 15, the apparatus 1502′ ofFIG. 16, and/or the like).

At 1210, the base station may identify a wakeup signal resourceassociated with a UE. For example, the base station may identify awakeup signal resource associated with a UE based at least in part on acontrol channel search space resource associated with the UE, asdescribed above in connection with FIGS. 9 and 10. The wakeup signalresource may map to the control channel search space resource, and mayprecede the control channel search space resource.

In some aspects, the wakeup signal resource maps to a plurality ofcontrol channel search space resources. In some aspects, the pluralityof control channel search space resources are associated with the UE. Insome aspects, the plurality of control channel search space resourcesare associated with a plurality of UEs.

In some aspects, the wakeup signal resource is identified based at leastin part on a periodicity or a time offset associated with the wakeupsignal resource and indicated to the UE. In some aspects, the wakeupsignal resource is identified based at least in part on at least one of:a UE identifier associated with the UE, a radio network temporaryidentifier (RNTI) associated with control channel communicationsmonitored by the UE, a signal-to-noise ratio associated with the UE, amaximum repetition level associated with the UE, an actual repetitionlevel associated with control channel communications for the UE, acarrier index associated with the control channel search space resource,or some combination thereof.

In some aspects, the wakeup signal resource occurs before the controlchannel search space resource with no intervening wakeup signalresources associated with the UE. In some aspects, the wakeup signalresource occurs a number of subframes before the control channel searchspace resource. In some aspects, the number of subframes is identifiedbased at least in part on at least one of: a signal-to-noise ratioassociated with the UE, a maximum repetition level associated with theUE, an actual repetition level associated with control channelcommunications for the UE, or some combination thereof.

At 1220, the base station may determine whether a control channel searchspace is to include control information associated with the UE. Forexample, the base station may determine whether a control channel searchspace is to include control information associated with the UE, asdescribed above in connection with FIGS. 9 and 10. The control channelsearch space may be associated with a control channel search spaceresource.

At 1230, the base station may selectively transmit a wakeup signal inthe wakeup signal resource based at least in part on determining whetherthe control channel search space includes control information associatedwith the UE. For example, the base station may selectively transmit awakeup signal in the wakeup signal resource based at least in part ondetermining whether the control channel search space is to includecontrol information associated with the UE, as described above inconnection with FIGS. 9 and 10. In some aspects, the wakeup signalindicates whether the UE is to initiate a wakeup procedure to monitorthe control channel search space resource or sleep during the controlchannel search space resource. In some aspects, the wakeup signalindicates one or more UEs that are to monitor the control channel searchspace resource.

In some aspects, the base station is configured to transmit the wakeupsignal when the control channel search space includes controlinformation associated with the UE. Additionally, or alternatively, thebase station is configured to skip transmission of the wakeup signalwhen the control channel search space does not include controlinformation associated with the UE.

Although FIG. 12 shows example blocks of a method of wirelesscommunication, in some aspects, the method may include additionalblocks, fewer blocks, different blocks, or differently arranged blocksthan those shown in FIG. 12. Additionally, or alternatively, two or moreblocks shown in FIG. 12 may be performed in parallel.

FIG. 13 is a conceptual data flow diagram 1300 illustrating the dataflow between different modules/means/components in an example apparatus1302. The apparatus 1302 may be a UE. In some aspects, the apparatus1302 includes a reception module 1304, an identification module 1306, amonitoring module 1308, and/or a transmission module 1310.

The reception module 1304 may receive, as data 1312 from a base station1350, information that identifies a control channel search spaceresource associated with the apparatus 1302. The reception module 1304may provide the information that identifies the control channel searchspace resource to the identification module 1306 as data 1314. Theidentification module 1306 may identify a wakeup signal resourceassociated with the apparatus 1302 based at least in part on a controlchannel search space resource associated with the apparatus 1302. Theidentification module 1306 may provide information that identifies thewakeup signal resource to the monitoring module 1308 as data 1316.

The monitoring module 1308 may monitor the wakeup signal resource for anindication of whether to monitor the control channel search spaceresource. In some aspects, the monitoring module 1308 and the receptionmodule 1304 may communicate using data 1318. For example, the monitoringmodule 1308 may provide an indication of the wakeup signal resource asdata 1318, and the reception module 1304 may monitor the wakeup signalresource. The reception module 1304 may provide an indication, based atleast in part on monitoring the wakeup signal resource, to themonitoring module 1308 as data 1318. The monitoring module 1308 mayinterpret the indication to determine whether to monitor the controlchannel search space resource, and may selectively monitor the controlchannel search space resource based at least in part on the indicationof whether to monitor the control channel search space resource. Forexample, the monitoring module 1308 may provide an indication of whetherto monitor the control channel search space resource to the receptionmodule 1304 as data 1318. The reception module 1304 may selectivelymonitor the control channel search space resource based at least in parton the indication.

In some aspects, one or more modules 1304, 1306, 1308 may provide data1320 to the transmission module 1310, and the transmission module 1310may provide data 1322 to the base station 1350. For example, thetransmission module 1310 may transmit data 1322 to the base station 1350based at least in part on the apparatus 1302 monitoring the controlchannel search space resource (e.g., when the control channel searchspace resource include control information instructing the apparatus1302 to transmit data 1322 to the base station 1350.

The apparatus may include additional modules that perform each of theblocks of the algorithm in the aforementioned flow chart of FIG. 11. Assuch, each block in the aforementioned flow chart of FIG. 11 may beperformed by a module, and the apparatus may include one or more ofthose modules. The modules may be one or more hardware componentsspecifically configured to carry out the stated processes/algorithm,implemented by a processor configured to perform the statedprocesses/algorithm, stored within a computer-readable medium forimplementation by a processor, or some combination thereof.

The number and arrangement of modules shown in FIG. 13 are provided asan example. In practice, there may be additional modules, fewer modules,different modules, or differently arranged modules than those shown inFIG. 13. Furthermore, two or more modules shown in FIG. 13 may beimplemented within a single module, or a single module shown in FIG. 13may be implemented as multiple, distributed modules. Additionally, oralternatively, a set of modules (e.g., one or more modules) shown inFIG. 13 may perform one or more functions described as being performedby another set of modules shown in FIG. 13.

FIG. 14 is a diagram 1400 illustrating an example of a hardwareimplementation for an apparatus 1302′ employing a processing system1402. The apparatus 1302′ may be a UE.

The processing system 1402 may be implemented with a bus architecture,represented generally by the bus 1404. The bus 1404 may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system 1402 and the overall designconstraints. The bus 1404 links together various circuits including oneor more processors and/or hardware modules, represented by the processor1406, the modules 1304, 1306, 1308, and/or 1310, and thecomputer-readable medium/memory 1408. The bus 1404 may also link variousother circuits such as timing sources, peripherals, voltage regulators,and power management circuits, which are well known in the art, andtherefore, will not be described any further.

The processing system 1402 may be coupled to a transceiver 1410. Thetransceiver 1410 is coupled to one or more antennas 1412. Thetransceiver 1410 provides a means for communicating with various otherapparatus over a transmission medium. The transceiver 1410 receives asignal from the one or more antennas 1412, extracts information from thereceived signal, and provides the extracted information to theprocessing system 1402, specifically the reception module 1304. Inaddition, the transceiver 1410 receives information from the processingsystem 1402, specifically the transmission module 1310, and based atleast in part on the received information, generates a signal to beapplied to the one or more antennas 1412. The processing system 1402includes a processor 1406 coupled to a computer-readable medium/memory1408. The processor 1406 is responsible for general processing,including the execution of software stored on the computer-readablemedium/memory 1408. The software, when executed by the processor 1406,causes the processing system 1402 to perform the various functionsdescribed supra for any particular apparatus. The computer-readablemedium/memory 1408 may also be used for storing data that is manipulatedby the processor 1406 when executing software. The processing systemfurther includes at least one of the modules 1304, 1306, 1308, and/or1310. The modules may be software modules running in the processor 1406,resident/stored in the computer readable medium/memory 1408, one or morehardware modules coupled to the processor 1406, or some combinationthereof. The processing system 1402 may be a component of the UE 120 andmay include the memory 282 and/or at least one of the TX MIMO processor266, the RX processor 258, and/or the controller/processor 280.

In some aspects, the apparatus 1302/1302′ for wireless communicationincludes means for identifying a wakeup signal resource associated withthe UE, means for monitoring the wakeup signal resource, means forselectively monitoring the control channel search space resource, and/orthe like. The aforementioned means may be one or more of theaforementioned modules of the apparatus 1302 and/or the processingsystem 1402 of the apparatus 1302′ configured to perform the functionsrecited by the aforementioned means. As described supra, the processingsystem 1402 may include the TX MIMO processor 266, the RX processor 258,and/or the controller/processor 280. As such, in one configuration, theaforementioned means may be the TX MIMO processor 266, the RX processor258, and/or the controller/processor 280 configured to perform thefunctions recited by the aforementioned means.

FIG. 14 is provided as an example. Other examples are possible and maydiffer from what was described in connection with FIG. 14.

FIG. 15 is a conceptual data flow diagram 1500 illustrating the dataflow between different modules/means/components in an example apparatus1502. The apparatus 1502 may be a base station. In some aspects, theapparatus 1502 includes a reception module 1504, an identificationmodule 1506, a determining module 1508, and/or a transmission module1510.

The reception module 1504 may receive data 1512 from a device 1550, suchas a UE or a network device. For example, the reception module 1504 mayreceive information, associated with the UE, to be used to identify awakeup signal resource associated with the UE (e.g., a UE identifierand/or the like). The reception module 1504 may provide such informationto the identification module 1506 as data 1514. The identificationmodule 1506 may identify a wakeup signal resource associated with a UEbased at least in part on a control channel search space resourceassociated with the UE (e.g., determined based at least in part on theinformation associated with the UE). The identification module 1506 mayprovide information that identifies the control channel search spaceresource to the determining module 1508 as data 1516.

The determining module 1508 may determine whether a control channelsearch space, associated with the control channel search space resource,includes control information associated with the UE. The determiningmodule 1508 may provide an indication of whether the control channelsearch space includes the control information to the transmission module1510 as data 1518. The transmission module 1510 may selectivelytransmit, to the UE as data 1520, a wakeup signal in the wakeup signalresource based at least in part on determining whether the controlchannel search space includes control information associated with theUE.

The apparatus may include additional modules that perform each of theblocks of the algorithm in the aforementioned flow chart of FIG. 12. Assuch, each block in the aforementioned flow chart of FIG. 12 may beperformed by a module, and the apparatus may include one or more ofthose modules. The modules may be one or more hardware componentsspecifically configured to carry out the stated processes/algorithm,implemented by a processor configured to perform the statedprocesses/algorithm, stored within a computer-readable medium forimplementation by a processor, or some combination thereof.

The number and arrangement of modules shown in FIG. 15 are provided asan example. In practice, there may be additional modules, fewer modules,different modules, or differently arranged modules than those shown inFIG. 15. Furthermore, two or more modules shown in FIG. 15 may beimplemented within a single module, or a single module shown in FIG. 15may be implemented as multiple, distributed modules. Additionally, oralternatively, a set of modules (e.g., one or more modules) shown inFIG. 15 may perform one or more functions described as being performedby another set of modules shown in FIG. 15.

FIG. 16 is a diagram 1600 illustrating an example of a hardwareimplementation for an apparatus 1502′ employing a processing system1602. The apparatus 1502′ may be a base station.

The processing system 1602 may be implemented with a bus architecture,represented generally by the bus 1604. The bus 1604 may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system 1602 and the overall designconstraints. The bus 1604 links together various circuits including oneor more processors and/or hardware modules, represented by the processor1606, the modules 1504, 1506, 1508, 1510, and the computer-readablemedium/memory 1608. The bus 1604 may also link various other circuitssuch as timing sources, peripherals, voltage regulators, and powermanagement circuits, which are well known in the art, and therefore,will not be described any further.

The processing system 1602 may be coupled to a transceiver 1610. Thetransceiver 1610 is coupled to one or more antennas 1612. Thetransceiver 1610 provides a means for communicating with various otherapparatus over a transmission medium. The transceiver 1610 receives asignal from the one or more antennas 1612, extracts information from thereceived signal, and provides the extracted information to theprocessing system 1602, specifically the reception module 1504. Inaddition, the transceiver 1610 receives information from the processingsystem 1602, specifically the transmission module 1510, and based atleast in part on the received information, generates a signal to beapplied to the one or more antennas 1612. The processing system 1602includes a processor 1606 coupled to a computer-readable medium/memory1608. The processor 1606 is responsible for general processing,including the execution of software stored on the computer-readablemedium/memory 1608. The software, when executed by the processor 1606,causes the processing system 1602 to perform the various functionsdescribed supra for any particular apparatus. The computer-readablemedium/memory 1608 may also be used for storing data that is manipulatedby the processor 1606 when executing software. The processing system1602 further includes at least one of the modules 1504, 1506, 1508,and/or 1510. The modules may be software modules running in theprocessor 1606, resident/stored in the computer readable medium/memory1608, one or more hardware modules coupled to the processor 1606, orsome combination thereof. The processing system 1602 may be a componentof the base station 110 and may include the memory 242 and/or at leastone of the TX MIMO processor 230, the RX processor 238, and/or thecontroller/processor 240.

In some aspects, the apparatus 1502/1502′ for wireless communicationincludes means for identifying a wakeup signal resource associated witha UE, means for determining whether a control channel search space is toinclude control information associated with the UE, means forselectively transmitting a wakeup signal in the wakeup signal resource,and/or the like. The aforementioned means may be one or more of theaforementioned modules of the apparatus 1502 and/or the processingsystem 1602 of the apparatus 1502′ configured to perform the functionsrecited by the aforementioned means. As described supra, the processingsystem 1602 may include the TX MIMO processor 230, the RX processor 238,and/or the controller/processor 240. As such, in one configuration, theaforementioned means may be the TX processor 230, the RX processor 238,and/or the controller/processor 240 configured to perform the functionsrecited by the aforementioned means.

FIG. 16 is provided as an example. Other examples are possible and maydiffer from what was described in connection with FIG. 16.

It is understood that the specific order or hierarchy of blocks in theprocesses/flow charts disclosed is an illustration of exampleapproaches. Based upon design preferences, it is understood that thespecific order or hierarchy of blocks in the processes/flow charts maybe rearranged. Further, some blocks may be combined or omitted. Theaccompanying method claims present elements of the various blocks in asample order, and are not meant to be limited to the specific order orhierarchy presented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” The word “exemplary” is used hereinto mean “serving as an example, instance, or illustration.” Any aspectdescribed herein as “exemplary” is not necessarily to be construed aspreferred or advantageous over other aspects. Unless specifically statedotherwise, the term “some” refers to one or more. Combinations such as“at least one of A, B, or C,” “at least one of A, B, and C,” and “A, B,C, or any combination thereof” include any combination of A, B, and/orC, and may include multiples of A, multiples of B, or multiples of C.Specifically, combinations such as “at least one of A, B, or C,” “atleast one of A, B, and C,” and “A, B, C, or any combination thereof” maybe A only, B only, C only, A and B, A and C, B and C, or A and B and C,where any such combinations may contain one or more member or members ofA, B, or C. All structural and functional equivalents to the elements ofthe various aspects described throughout this disclosure that are knownor later come to be known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims. No claim element is tobe construed as a means plus function unless the element is expresslyrecited using the phrase “means for.”

What is claimed is:
 1. A method of wireless communication, comprising:identifying, by a user equipment (UE), a wakeup signal resourceassociated with the UE based at least in part on a control channelsearch space resource associated with the UE, wherein the wakeup signalresource maps to the control channel search space resource and precedesthe control channel search space resource; monitoring, by the UE, thewakeup signal resource for an indication of whether to monitor thecontrol channel search space resource; and selectively monitoring, bythe UE, the control channel search space resource based at least in parton the indication of whether to monitor the control channel search spaceresource.
 2. The method of claim 1, wherein the UE is configured toinitiate a wakeup procedure to monitor the control channel search spaceresource when the monitoring of the wakeup signal resource indicatesthat the control channel search space resource is to be monitored, orwherein the UE is configured to sleep during the control channel searchspace resource when the monitoring of the wakeup signal resourceindicates that the control channel search space resource is not to bemonitored.
 3. The method of claim 1, wherein the wakeup signal resourcemaps to a plurality of control channel search space resources.
 4. Themethod of claim 3, wherein the plurality of control channel search spaceresources are associated with the UE.
 5. The method of claim 3, whereinthe plurality of control channel search space resources are associatedwith a plurality of UEs.
 6. The method of claim 1, wherein the wakeupsignal resource is identified based at least in part on a periodicity ora time offset associated with the wakeup signal resource.
 7. The methodof claim 1, wherein the wakeup signal resource is identified based atleast in part on at least one of: a UE identifier associated with theUE, a radio network temporary identifier (RNTI) associated with controlchannel communications monitored by the UE, a signal-to-noise ratioassociated with the UE, a maximum repetition level associated with theUE, an actual repetition level associated with control channelcommunications for the UE, a carrier index associated with the controlchannel search space resource, or some combination thereof.
 8. Themethod of claim 1, wherein the wakeup signal resource occurs before thecontrol channel search space resource with no intervening wakeup signalresources associated with the UE.
 9. The method of claim 1, wherein thewakeup signal resource occurs a number of subframes before the controlchannel search space resource.
 10. The method of claim 9, wherein thenumber of subframes is identified based at least in part on at least oneof: a signal-to-noise ratio associated with the UE, a maximum repetitionlevel associated with the UE, an actual repetition level associated withcontrol channel communications for the UE, or some combination thereof.11. The method of claim 1, wherein the UE is configured to monitor thecontrol channel search space resource when a wakeup signal is present inthe wakeup signal resource, or wherein the UE is configured to skipmonitoring of the control channel search space resource when the wakeupsignal is absent from the wakeup signal resource.
 12. The method ofclaim 1, wherein the wakeup signal resource corresponds to a number ofresource elements associated with a wakeup signal that is transmittedover a plurality of resource elements; and wherein the number ofresource elements over which the UE is configured to monitor for thewakeup signal is determined based at least in part on a maximumrepetition level of control channel communications or a signal-to-noiseratio associated with the UE.
 13. The method of claim 12, wherein alength of the wakeup signal is configured based at least in part on atleast one of: a maximum repetition level associated with a controlchannel that includes the control channel search space resource, anactual repetition level associated with the control channel, adetermination of whether the wakeup signal is transmitted using transmitdiversity, a determination of whether the wakeup signal is transmittedusing frequency hopping, a discontinuous reception cycle lengthassociated with the UE, a radio resource control (RRC) configurationmessage, or some combination thereof.
 14. The method of claim 1, whereinthe UE is configured to identify or monitor the wakeup signal resourcebased at least in part on a determination that the UE is associated witha repetition level or a signal-to-noise ratio that satisfies acondition.
 15. The method of claim 1, wherein a payload size of a wakeupsignal in the wakeup signal resource is less than a payload size usedfor legacy downlink control information in a control channel thatincludes the control channel search space resource, wherein the wakeupsignal is also carried on a physical downlink control channel (PDCCH).16. The method of claim 1, wherein a wakeup signal in the wakeup signalresource indicates one or more UEs that are to monitor the controlchannel search space resource.
 17. The method of claim 1, wherein thewakeup signal resource is different for different UEs monitoring thesame paging resource.
 18. The method of claim 1, wherein the wakeupsignal resource is identified or monitored based at least in part on awakeup signal mode determined based at least in part on whether a wakeupsignal is being used for connected mode discontinuous reception (CDRX).19. A method of wireless communication, comprising: identifying, by abase station, a wakeup signal resource associated with a user equipment(UE) based at least in part on a control channel search space resourceassociated with the UE, wherein the wakeup signal resource maps to thecontrol channel search space resource and precedes the control channelsearch space resource; determining, by the base station, whether acontrol channel search space, associated with the control channel searchspace resource, is to include control information associated with theUE; and selectively transmitting, by the base station, a wakeup signalin the wakeup signal resource based at least in part on determiningwhether the control channel search space is to include controlinformation associated with the UE.
 20. The method of claim 19, whereinthe wakeup signal indicates whether the UE is to initiate a wakeupprocedure to monitor the control channel search space resource or sleepduring the control channel search space resource.
 21. The method ofclaim 19, wherein the wakeup signal resource maps to a plurality ofcontrol channel search space resources.
 22. The method of claim 21,wherein the plurality of control channel search space resources areassociated with the UE.
 23. The method of claim 21, wherein theplurality of control channel search space resources are associated witha plurality of UEs.
 24. The method of claim 19, wherein the wakeupsignal resource is identified based at least in part on a periodicity ora time offset associated with the wakeup signal resource and indicatedto the UE.
 25. The method of claim 19, wherein the wakeup signalresource is identified based at least in part on at least one of: a UEidentifier associated with the UE, a radio network temporary identifier(RNTI) associated with control channel communications monitored by theUE, a signal-to-noise ratio associated with the UE, a maximum repetitionlevel associated with the UE, an actual repetition level associated withcontrol channel communications for the UE, a carrier index associatedwith the control channel search space resource, or some combinationthereof.
 26. The method of claim 19, wherein the wakeup signal resourceoccurs before the control channel search space resource with nointervening wakeup signal resources associated with the UE.
 27. Themethod of claim 19, wherein the wakeup signal resource occurs a numberof subframes before the control channel search space resource.
 28. Themethod of claim 27, wherein the number of subframes is identified basedat least in part on at least one of: a signal-to-noise ratio associatedwith the UE, a maximum repetition level associated with the UE, anactual repetition level associated with control channel communicationsfor the UE, or some combination thereof.
 29. The method of claim 19,wherein the base station is configured to transmit the wakeup signalwhen the control channel search space is to include control informationassociated with the UE, or wherein the base station is configured toskip transmission of the wakeup signal when the control channel searchspace is not to include control information associated with the UE. 30.The method of claim 19, wherein a length of the wakeup signal isconfigured based at least in part on at least one of: a maximumrepetition level associated with a control channel that includes thecontrol channel search space resource, a determination of whether thewakeup signal is transmitted using transmit diversity, a determinationof whether the wakeup signal is transmitted using frequency hopping, adiscontinuous reception cycle length associated with the UE, a radioresource control (RRC) configuration message, or some combinationthereof.
 31. The method of claim 19, wherein a payload size of thewakeup signal is less than a payload size used for legacy downlinkcontrol information in a control channel that includes the controlchannel search space resource.
 32. The method of claim 19, wherein thewakeup signal indicates one or more UEs that are to monitor the controlchannel search space resource.
 33. A user equipment (UE) for wirelesscommunication, comprising: memory; and one or more processors coupled tothe memory, the memory and the one or more processors configured to:identify a wakeup signal resource associated with the UE based at leastin part on a control channel search space resource associated with theUE, wherein the wakeup signal resource maps to the control channelsearch space resource and precedes the control channel search spaceresource; monitor the wakeup signal resource for an indication ofwhether to monitor the control channel search space resource; andselectively monitor the control channel search space resource based atleast in part on the indication of whether to monitor the controlchannel search space resource.
 34. A base station for wirelesscommunication, comprising: memory; and one or more processors coupled tothe memory, the memory and the one or more processors configured to:identify a wakeup signal resource associated with a user equipment (UE)based at least in part on a control channel search space resourceassociated with the UE, wherein the wakeup signal resource maps to thecontrol channel search space resource and precedes the control channelsearch space resource; determine whether a control channel search space,associated with the control channel search space resource, is to includecontrol information associated with the UE; and selectively transmit awakeup signal in the wakeup signal resource based at least in part ondetermining whether the control channel search space is to includecontrol information associated with the UE.